Why did those pilot whales in Florida beach themselves?

In this photo provided by SeaWorld Parks & Entertainment, people attend to one of five rescued pilot whales Sunday, at Florida Atlantic University's Harbor Branch Institute in Fort Pierce, Fla. The five whales were among a group of 22 whales beached in South Florida on Saturday. The rest died of natural causes or were euthanized.

Officials from the U.S. National Park Service, Florida Fish and Wildlife and the National Oceanic and Atmospheric Administration were checking the whales and trying to determine whether they could be coaxed back out to sea, Segelson said.

She said pilot whales, which are considered highly intelligent, are a species that commonly strand themselves on beaches around the globe.

Such incidents have often been blamed on infestations of parasites that affect the whales' brains and their ability to stay on course. They normally stick to deep waters, where they feed on a diet that includes squid and octopus.

"Right now the cause isn't clear," said Segelson.

Male pilot whales, which are normally dark black and larger than their female counterparts, can grow to about 20 feet (6 meters) and tip the scales at as much as three tons.